While a variety of pumping systems for these and other purposes have hitherto been proposed and put into practical utility, it has been found that all of them are designed to operate on the pumping principles which require the pumping members to be driven at a relatively high rate of periodic displacement, e.g. rotation. As a result, it is quite common that the operations give rise to considerable noise. Most of the input electrical power is lost in sound, vibration, frictional resistance and heat. It has thus been observed that the power efficiency is as low as 5 to 10%.